I worked in this building in the 1980s, after its renovation, and the main things I remember were noise, and terrible ventilation.

The questionable floor is also the ceiling of the basement, which housed the city's post office. The rest of the building consisted of offices.

Perhaps I'm not looking at the right floor, but why is it assumed that the floor is glass? It appears to me that it could certainly be tile or stone (and when I've visited the OPOB on several occasions I've not noticed anything too unusual about the floor, like it being glass).

[Examine it carefully, along with the next photo down. - Dave]

...that the whole floor is glass? It looks to me like there are skylights around the exterior but the middle looks, to me at least; like bricks or maybe tiles. The skylights were to add daylight to a drab concrete basement. Having lived in DC all my life and worked in several government buildings I can speak for the dull grey "dungeon" feel of most of the basements of government buldings. - Malik

[Click below to enlarge. - Dave]

Perhaps this is where the term "Daylight Basement" came from.

From the GSA website:
http://www.gsa.gov/Portal/gsa/ep/contentView.do?P=PMHP&contentId=19389&c...

"The most remarkable feature inside is the nine-story light court topped by an enormous skylight that floods the interior with natural light. When it was built, the room was the largest, uninterrupted interior space in Washington."

Skylights? The better to see you with, my dear! Also, with the open atrium (as it is called now) and exterior windows that could actually be opened (something rarely seen in today's buildngs) the circulation of air is enhanced. Think of those hot and humid days in DC without air conditioning.

[The question was, why is the "floor" also a skylight. - Dave]

Flag Day used to be a very big patriotic holiday, celebrated like the Fourth of July. Perhaps it faded away because it is on June 14th and that is very close to Independence Day and not far from Memorial Day, both of which commemmorate similar patriotism. I wonder how many people today are even aware of Flag Day or its date. You can see by the extensive decorations that it used to be one very big deal. And the beat goes on.

Interesting setup, seems to be one huge skylight under another. Wonder why they did it that way.